Numerous fireplaces include ash pit doors which open upwardly through the floor of a fireplace and many of these ash pits are now being converted to combustion air inlets in order that combustion air for the fireplace may be drawn from a cool basement portion of a residence as opposed to drawing combustion air through the open side of the fireplace. In this manner, the open side of the fireplace may be closed by transparent fireplace doors and a considerable reduction in the flow of outside air passing inwardly through voids in a residence construction in order to replace combustion air admitted into a fireplace is realized.
However, most fireplace ash pits open upwardly through the floor of the associated fireplace in a central portion therein and combustion air being discharged from an ash pit converted to a fresh air inlet causes combustion air to flow rapidly toward a relatively small area of the solid fuel supported from a fireplace grate disposed over the combustion air inlet with the result that the burning rate of solid fuel within the fireplace is excessive.
Accordingly, a need exists for structure by which an ash pit converted to a combustion air inlet for a fireplace may have an air diverter operatively associated therewith so that combustion air being discharged from the ash pit upwardly into the fireplace may be diverted and supplied to remote portions of an accumulation of solid fuel being burned in an associated fireplace grate.
Also, a need exists to provide means whereby the combustion air admitted into a fireplace through a converted ash pit may be throttled to the desired rate.
Various forms of air throttling and diverting structures for use in conjunction with ash pits and other similar air inlets and which include some of the general structural and operational features of the instant invention are disclosed in U.S. Pat. Nos. 4,106,475, 4,136,666, 4,184,474, 4,186,719 and 4,374,515.